1. Field of the Invention
The present invention relates to an ozonizer.
2. Related Art
An ozonizer has been heretofore known, for example, in Japanese Patent Publication No. 4-74281 Publication, in which at least one anode and one cathode are opposedly arranged so as to form a discharge space therebetween, and raw gases such as oxygen, air or the like are allowed to flow into the discharge space to generate ozone. According to the invention disclosed in the aforementioned publication, a number of plane portions arrayed on one and the same plane are arranged on both outer sides of a metal flat plate, parts other than these plane portions are in the form of a recess, a number of small holes for communication of both side portions are bored to provide one side electrode, and a mating electrode is superposed on both sides of the one side electrode through a ceramic plate. More specifically, as shown in FIG. 7, an anode plate 91 formed from a metal flat plate are formed with recesses 93 between both sides (plane portions 92) so as to correspond to each other on both sides, and through-holes 94 are formed in portions formed with the recesses 93 so that both the recesses 93 are communicated with each other. On both sides of the anode plate 91 are arranged plate-like dielectric layers 95 formed of ceramic in face contact with the plane portions 92, and on both outer sides of the dielectric layers 95 are stacked metal cathode plates 96. A power source not shown is connected to the anode plate 91 and the cathode plates 96.
In the aforementioned first constitution, a high voltage high frequency voltage is applied between one electrode (anode plate 91) and the mating electrode (cathode 96) to forma discharge electric field in the recess 93, a creeping discharge is generated in the recess 93 in the outer peripheral portion of the plane portion 92, and a silent discharge is generated at a part (in the recess 93) away from the plane portion 92 to thereby ozonize the raw gas passing through the recess 93. Further, the passing raw gas freely passes through the small hole (through-hole 94) between both sides to thereby complicate a flowpassage of the passing gas, to generate an eddy current at a part to increase the probability in contact with the discharge electric field and the contact time, and to average the flow rate between both sides, thus preventing a variation of the ozonizing efficiency.
There is a further proposal as disclosed in Japanese Patent Publication No. 61-32242 Publication. According to the invention disclosed therein, a filler formed from a metal wire is provided as one electrode in contact with one surface of a solid dielectric, and a filler similar to that as described above or a metal sheet is provided as an opposite electrode in contact with the other surface of the dielectric.
According to the aforementioned second constitution, a filler formed of a metal wire material is used as a discharge electrode and/or a feed electrode (for example, a wire cloth may be used, or a filler formed from a metal wire or a wire cloth such as metal wool may be used instead) to adjust the amount of space in the periphery of the electrode (a diameter of a metal wire of the filler type electrode, a dimension and a shape of the filler, the amount of filler and a position relative to the opposite electrode are suitably determined) whereby even at a lower voltage than prior art (a normal silent charging type ozonizer), the discharge can be stabilized to increase the generating efficiency of ozone.
In the aforementioned first constitution, when the raw gas passes through the discharge generating space (recess 93), energy is obtained mainly from an electron so that an oxygen molecule is dissociated into an oxygen atom, and after this, reacted with the oxygen molecule to generate ozone. Electric power consumed for the discharge is consumed by numberless discharges generated between the ceramic dielectric layer 95 and the anode plate 91 by a voltage applied by a power source and a current flowing through the plane portions in contact with the dielectric layer 95 and the anode plate 91. Here, the discharge generated between the dielectric layer 95 and the anode 91 by the voltage contributes to apply energy to the oxygen molecule while the current flowing at the plane portions 92 in contact with the dielectric layer 95 and the anode 91 does not contribute to reception of energy to the oxygen molecule because no gas flows to the portions as described but substantially all the energy is converted into heat for consumption. In this constitution having a number of plane portions 92, there are many power which is invalid with respect to power introduced, posing a problem in that the ozone generating efficiency is poor.
In the aforementioned second constitution, in the case where a wire cloth is used as a filler, that is, in the case where a wire cloth is used as a discharge electrode (anode), it is considered that a contact area between the solid electric and the discharge electrode is smaller than that of the first constitution but there is a problem as mentioned later.
FIG. 4 shows a general wire cloth. This drawing shows one of Industrial Woven Wire Cloth set forth in JIS G 3556. This wire cloth has a shape in which longitudinal wires and lateral wires having a circular section are interconnected each other while keeping a predetermined spacing.
It is known that when the dielectric comes in contact with the discharge electrode, an intense discharge occurs in the vicinity of the apex of the contact portion. In the case where the wire cloth as described above is used as a discharge electrode, since the all the periphery of the apex of the contact portion has a curved surface, the space in the vicinity of the contact portion is narrow, and the raw gas is hard to flow into the space. For this reason, the rate is low in which the intense discharge contributes to apply energy to the oxygen molecule. Further, at the time of assembling so that the wire cloth as the discharge electrode comes in contact with the dielectric, when a pressing force acts therebetween, the contact area easily increases, and a face contact portion is substantially formed. Therefore, there are much power which is invalid with respect to power introduced.
Further, the wire cloth is low in rigidity since their stocks are not connected integrally. In the case of the construction in which a wire cloth as a discharge electrode is sandwiched by dielectric as in an ozonizer of a flat plate type, it is difficult to keep a discharge generating space in a predetermined spacing, failing to obtain an even discharge and an even flow of raw gas. Therefore, there is a problem in that discharge energy cannot be effectively used.
In the case of using metal wool, there is the following problem in addition to the problem of holding a discharge generating space as described above. Since metal wool is indefinite in shape, it is difficult to make density of parts of a filler uniform. Therefore, when the raw gas passes through the discharge generating space, that is, a filler member, the raw gas mainly passes through a portion where density of the filler is low. Therefore, there poses a problem in that discharge energy cannot be effectively used.
Accordingly, also in the second constitution, there is much power which is invalid with respect to power introduced, and the ozone generating efficiency is poor.
This invention has been achieved for solving the problems as noted above with respect to prior art, and provides an ozonizer which is less in power which is invalid with respect to power introduced, and which is good in ozone generating efficiency.